Manufacturing semiconductor wafers or similar articles such as flat panel displays, hard disk media, CD glass, etc., requires chemical-mechanical polishing steps at various points in the processing sequence. Abrasives based on either alumina or silica, along with chemical additives, are typically used in these polishing steps. After the polishing is done, a cleaning step is needed to remove the slurries left by the polishing step. The slurries have typically been removed with brush cleaning. While brush cleaning has been successfully used, it has certain disadvantages, e.g., in cost and speed, primarily resulting from the need for mechanical movement between the brush and the wafer surface. While a purely chemical cleaning process can avoid the disadvantages of brush cleaning, difficulties have remained in developing a chemical cleaning process which is effective in removing the slurry, while at the same time not contaminating or degrading the wafer or work piece.
A new chemical mixture has now been developed which effectively removes the slurries, without mechanically brushing or scrubbing, and without degrading the work piece.
In a first aspect of the invention, the cleaning mixture includes a caustic, an anionic surfactant, a non-ionic surfactant, and water. The caustic preferably has an ionic concentration in the range of 0.5 to 10.00000N, and more preferably an ionic concentration in the range of 0.10 to 0.01N. The ionic concentration of the caustic advantageously provides an etch rate on the surface of from 1 to 100 Angstroms per minute.
In a method for cleaning slurries from a semiconductor article surface, the article is first rinsed with deionized water. The article is then preheated with hot deionized water. The chemical cleaning mixture is applied to the article surface. The surface is then rinsed and dried.